Z8F640x/Z8F480x/Z8F320x/Z8F240x/Z8F160x
Z8 Encore!®
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Low-Power Modes
Overview
The Z8F640x family products contain power-saving features. The highest level of power
reduction is provided by Stop mode. The next level of power reduction is provided by the
Halt mode.
Stop Mode
Execution of the eZ8 CPU’s STOP instruction places the Z8F640x family device into Stop
mode. In Stop mode, the operating characteristics are:
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Primary crystal oscillator is stopped
System clock is stopped
eZ8 CPU is stopped
Program counter (PC) stops incrementing
Watch-Dog Timer’s internal RC oscillator continues to operate
If enabled, the Watch-Dog Timer continues to operate
All other on-chip peripherals are idle
To minimize current in Stop mode, all GPIO pins that are configured as digital inputs must
be driven to one of the supply rails (VCC or GND). The Z8F640x family device can be
brought out of Stop mode using Stop Mode Recovery. For more information on STOP
Mode Recovery refer to the Reset and Stop Mode Recovery chapter.
Halt Mode
Execution of the eZ8 CPU’s HALT instruction places the Z8F640x family device into Halt
mode. In Halt mode, the operating characteristics are:
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Primary crystal oscillator is enabled and continues to operate
System clock is enabled and continues to operate
eZ8 CPU is idle
Program counter (PC) stops incrementing
PS017610-0404
Low-Power Modes
ZILOG [ ZILOG, INC. ]
